union_vfsops.c revision 1.1
1 /* $NetBSD: union_vfsops.c,v 1.1 2003/03/16 08:26:54 jdolecek Exp $ */ 2 3 /* 4 * Copyright (c) 1994 The Regents of the University of California. 5 * Copyright (c) 1994 Jan-Simon Pendry. 6 * All rights reserved. 7 * 8 * This code is derived from software donated to Berkeley by 9 * Jan-Simon Pendry. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95 40 */ 41 42 /* 43 * Union Layer 44 */ 45 46 #include <sys/cdefs.h> 47 __KERNEL_RCSID(0, "$NetBSD: union_vfsops.c,v 1.1 2003/03/16 08:26:54 jdolecek Exp $"); 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/time.h> 52 #include <sys/proc.h> 53 #include <sys/vnode.h> 54 #include <sys/mount.h> 55 #include <sys/namei.h> 56 #include <sys/malloc.h> 57 #include <sys/filedesc.h> 58 #include <sys/queue.h> 59 #include <sys/stat.h> 60 61 #include <fs/union/union.h> 62 63 int union_mount __P((struct mount *, const char *, void *, struct nameidata *, 64 struct proc *)); 65 int union_start __P((struct mount *, int, struct proc *)); 66 int union_unmount __P((struct mount *, int, struct proc *)); 67 int union_root __P((struct mount *, struct vnode **)); 68 int union_quotactl __P((struct mount *, int, uid_t, caddr_t, struct proc *)); 69 int union_statfs __P((struct mount *, struct statfs *, struct proc *)); 70 int union_sync __P((struct mount *, int, struct ucred *, struct proc *)); 71 int union_vget __P((struct mount *, ino_t, struct vnode **)); 72 int union_fhtovp __P((struct mount *, struct fid *, struct vnode **)); 73 int union_checkexp __P((struct mount *, struct mbuf *, int *, 74 struct ucred **)); 75 int union_vptofh __P((struct vnode *, struct fid *)); 76 int union_sysctl __P((int *, u_int, void *, size_t *, void *, size_t, 77 struct proc *)); 78 79 /* 80 * Mount union filesystem 81 */ 82 int 83 union_mount(mp, path, data, ndp, p) 84 struct mount *mp; 85 const char *path; 86 void *data; 87 struct nameidata *ndp; 88 struct proc *p; 89 { 90 int error = 0; 91 struct union_args args; 92 struct vnode *lowerrootvp = NULLVP; 93 struct vnode *upperrootvp = NULLVP; 94 struct union_mount *um = 0; 95 struct ucred *cred = 0; 96 char *cp; 97 int len; 98 size_t size; 99 100 #ifdef UNION_DIAGNOSTIC 101 printf("union_mount(mp = %p)\n", mp); 102 #endif 103 104 if (mp->mnt_flag & MNT_GETARGS) { 105 um = MOUNTTOUNIONMOUNT(mp); 106 if (um == NULL) 107 return EIO; 108 args.target = NULL; 109 args.mntflags = um->um_op; 110 return copyout(&args, data, sizeof(args)); 111 } 112 /* 113 * Update is a no-op 114 */ 115 if (mp->mnt_flag & MNT_UPDATE) { 116 /* 117 * Need to provide. 118 * 1. a way to convert between rdonly and rdwr mounts. 119 * 2. support for nfs exports. 120 */ 121 error = EOPNOTSUPP; 122 goto bad; 123 } 124 125 /* 126 * Get argument 127 */ 128 error = copyin(data, (caddr_t)&args, sizeof(struct union_args)); 129 if (error) 130 goto bad; 131 132 lowerrootvp = mp->mnt_vnodecovered; 133 VREF(lowerrootvp); 134 135 /* 136 * Find upper node. 137 */ 138 NDINIT(ndp, LOOKUP, FOLLOW, 139 UIO_USERSPACE, args.target, p); 140 141 if ((error = namei(ndp)) != 0) 142 goto bad; 143 144 upperrootvp = ndp->ni_vp; 145 146 if (upperrootvp->v_type != VDIR) { 147 error = EINVAL; 148 goto bad; 149 } 150 151 um = (struct union_mount *) malloc(sizeof(struct union_mount), 152 M_UFSMNT, M_WAITOK); /* XXX */ 153 154 /* 155 * Keep a held reference to the target vnodes. 156 * They are vrele'd in union_unmount. 157 * 158 * Depending on the _BELOW flag, the filesystems are 159 * viewed in a different order. In effect, this is the 160 * same as providing a mount under option to the mount syscall. 161 */ 162 163 um->um_op = args.mntflags & UNMNT_OPMASK; 164 switch (um->um_op) { 165 case UNMNT_ABOVE: 166 um->um_lowervp = lowerrootvp; 167 um->um_uppervp = upperrootvp; 168 break; 169 170 case UNMNT_BELOW: 171 um->um_lowervp = upperrootvp; 172 um->um_uppervp = lowerrootvp; 173 break; 174 175 case UNMNT_REPLACE: 176 vrele(lowerrootvp); 177 lowerrootvp = NULLVP; 178 um->um_uppervp = upperrootvp; 179 um->um_lowervp = lowerrootvp; 180 break; 181 182 default: 183 error = EINVAL; 184 goto bad; 185 } 186 187 /* 188 * Unless the mount is readonly, ensure that the top layer 189 * supports whiteout operations 190 */ 191 if ((mp->mnt_flag & MNT_RDONLY) == 0) { 192 error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP); 193 if (error) 194 goto bad; 195 } 196 197 um->um_cred = p->p_ucred; 198 crhold(um->um_cred); 199 um->um_cmode = UN_DIRMODE &~ p->p_cwdi->cwdi_cmask; 200 201 /* 202 * Depending on what you think the MNT_LOCAL flag might mean, 203 * you may want the && to be || on the conditional below. 204 * At the moment it has been defined that the filesystem is 205 * only local if it is all local, ie the MNT_LOCAL flag implies 206 * that the entire namespace is local. If you think the MNT_LOCAL 207 * flag implies that some of the files might be stored locally 208 * then you will want to change the conditional. 209 */ 210 if (um->um_op == UNMNT_ABOVE) { 211 if (((um->um_lowervp == NULLVP) || 212 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) && 213 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL)) 214 mp->mnt_flag |= MNT_LOCAL; 215 } 216 217 /* 218 * Copy in the upper layer's RDONLY flag. This is for the benefit 219 * of lookup() which explicitly checks the flag, rather than asking 220 * the filesystem for it's own opinion. This means, that an update 221 * mount of the underlying filesystem to go from rdonly to rdwr 222 * will leave the unioned view as read-only. 223 */ 224 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY); 225 226 mp->mnt_data = um; 227 vfs_getnewfsid(mp); 228 229 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size); 230 memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size); 231 232 switch (um->um_op) { 233 case UNMNT_ABOVE: 234 cp = "<above>:"; 235 break; 236 case UNMNT_BELOW: 237 cp = "<below>:"; 238 break; 239 case UNMNT_REPLACE: 240 cp = ""; 241 break; 242 default: 243 cp = "<invalid>:"; 244 #ifdef DIAGNOSTIC 245 panic("union_mount: bad um_op"); 246 #endif 247 break; 248 } 249 len = strlen(cp); 250 memcpy(mp->mnt_stat.f_mntfromname, cp, len); 251 252 cp = mp->mnt_stat.f_mntfromname + len; 253 len = MNAMELEN - len; 254 255 (void) copyinstr(args.target, cp, len - 1, &size); 256 memset(cp + size, 0, len - size); 257 258 #ifdef UNION_DIAGNOSTIC 259 printf("union_mount: from %s, on %s\n", 260 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); 261 #endif 262 return (0); 263 264 bad: 265 if (um) 266 free(um, M_UFSMNT); 267 if (cred) 268 crfree(cred); 269 if (upperrootvp) 270 vrele(upperrootvp); 271 if (lowerrootvp) 272 vrele(lowerrootvp); 273 return (error); 274 } 275 276 /* 277 * VFS start. Nothing needed here - the start routine 278 * on the underlying filesystem(s) will have been called 279 * when that filesystem was mounted. 280 */ 281 /*ARGSUSED*/ 282 int 283 union_start(mp, flags, p) 284 struct mount *mp; 285 int flags; 286 struct proc *p; 287 { 288 289 return (0); 290 } 291 292 /* 293 * Free reference to union layer 294 */ 295 int 296 union_unmount(mp, mntflags, p) 297 struct mount *mp; 298 int mntflags; 299 struct proc *p; 300 { 301 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 302 struct vnode *um_rootvp; 303 int error; 304 int freeing; 305 306 #ifdef UNION_DIAGNOSTIC 307 printf("union_unmount(mp = %p)\n", mp); 308 #endif 309 310 if ((error = union_root(mp, &um_rootvp)) != 0) 311 return (error); 312 313 /* 314 * Keep flushing vnodes from the mount list. 315 * This is needed because of the un_pvp held 316 * reference to the parent vnode. 317 * If more vnodes have been freed on a given pass, 318 * the try again. The loop will iterate at most 319 * (d) times, where (d) is the maximum tree depth 320 * in the filesystem. 321 */ 322 for (freeing = 0; vflush(mp, um_rootvp, 0) != 0;) { 323 struct vnode *vp; 324 int n; 325 326 /* count #vnodes held on mount list */ 327 for (n = 0, vp = mp->mnt_vnodelist.lh_first; 328 vp != NULLVP; 329 vp = vp->v_mntvnodes.le_next) 330 n++; 331 332 /* if this is unchanged then stop */ 333 if (n == freeing) 334 break; 335 336 /* otherwise try once more time */ 337 freeing = n; 338 } 339 340 /* 341 * Ok, now that we've tried doing it gently, get out the hammer. 342 */ 343 344 if (mntflags & MNT_FORCE) 345 vflush(mp, um_rootvp, FORCECLOSE); 346 347 348 /* At this point the root vnode should have a single reference */ 349 if (um_rootvp->v_usecount > 1) { 350 vput(um_rootvp); 351 return (EBUSY); 352 } 353 354 #ifdef UNION_DIAGNOSTIC 355 vprint("union root", um_rootvp); 356 #endif 357 /* 358 * Discard references to upper and lower target vnodes. 359 */ 360 if (um->um_lowervp) 361 vrele(um->um_lowervp); 362 vrele(um->um_uppervp); 363 crfree(um->um_cred); 364 /* 365 * Release reference on underlying root vnode 366 */ 367 vput(um_rootvp); 368 /* 369 * And blow it away for future re-use 370 */ 371 vgone(um_rootvp); 372 /* 373 * Finally, throw away the union_mount structure 374 */ 375 free(mp->mnt_data, M_UFSMNT); /* XXX */ 376 mp->mnt_data = 0; 377 return (0); 378 } 379 380 int 381 union_root(mp, vpp) 382 struct mount *mp; 383 struct vnode **vpp; 384 { 385 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 386 int error; 387 int loselock; 388 389 /* 390 * Return locked reference to root. 391 */ 392 VREF(um->um_uppervp); 393 if ((um->um_op == UNMNT_BELOW) && 394 VOP_ISLOCKED(um->um_uppervp)) { 395 loselock = 1; 396 } else { 397 vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY); 398 loselock = 0; 399 } 400 if (um->um_lowervp) 401 VREF(um->um_lowervp); 402 error = union_allocvp(vpp, mp, 403 (struct vnode *) 0, 404 (struct vnode *) 0, 405 (struct componentname *) 0, 406 um->um_uppervp, 407 um->um_lowervp, 408 1); 409 410 if (error) { 411 if (!loselock) 412 VOP_UNLOCK(um->um_uppervp, 0); 413 vrele(um->um_uppervp); 414 if (um->um_lowervp) 415 vrele(um->um_lowervp); 416 } else { 417 if (loselock) 418 VTOUNION(*vpp)->un_flags &= ~UN_ULOCK; 419 } 420 421 return (error); 422 } 423 424 /*ARGSUSED*/ 425 int 426 union_quotactl(mp, cmd, uid, arg, p) 427 struct mount *mp; 428 int cmd; 429 uid_t uid; 430 caddr_t arg; 431 struct proc *p; 432 { 433 434 return (EOPNOTSUPP); 435 } 436 437 int 438 union_statfs(mp, sbp, p) 439 struct mount *mp; 440 struct statfs *sbp; 441 struct proc *p; 442 { 443 int error; 444 struct union_mount *um = MOUNTTOUNIONMOUNT(mp); 445 struct statfs mstat; 446 int lbsize; 447 448 #ifdef UNION_DIAGNOSTIC 449 printf("union_statfs(mp = %p, lvp = %p, uvp = %p)\n", mp, 450 um->um_lowervp, um->um_uppervp); 451 #endif 452 453 memset(&mstat, 0, sizeof(mstat)); 454 455 if (um->um_lowervp) { 456 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p); 457 if (error) 458 return (error); 459 } 460 461 /* now copy across the "interesting" information and fake the rest */ 462 lbsize = mstat.f_bsize; 463 sbp->f_blocks = mstat.f_blocks - mstat.f_bfree; 464 sbp->f_files = mstat.f_files - mstat.f_ffree; 465 466 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p); 467 if (error) 468 return (error); 469 470 sbp->f_type = 0; 471 sbp->f_flags = mstat.f_flags; 472 sbp->f_bsize = mstat.f_bsize; 473 sbp->f_iosize = mstat.f_iosize; 474 475 /* 476 * The "total" fields count total resources in all layers, 477 * the "free" fields count only those resources which are 478 * free in the upper layer (since only the upper layer 479 * is writable). 480 */ 481 482 if (mstat.f_bsize != lbsize) 483 sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize; 484 sbp->f_blocks += mstat.f_blocks; 485 sbp->f_bfree = mstat.f_bfree; 486 sbp->f_bavail = mstat.f_bavail; 487 sbp->f_files += mstat.f_files; 488 sbp->f_ffree = mstat.f_ffree; 489 490 if (sbp != &mp->mnt_stat) { 491 memcpy(&sbp->f_fsid, &mp->mnt_stat.f_fsid, sizeof(sbp->f_fsid)); 492 memcpy(sbp->f_mntonname, mp->mnt_stat.f_mntonname, MNAMELEN); 493 memcpy(sbp->f_mntfromname, mp->mnt_stat.f_mntfromname, MNAMELEN); 494 } 495 strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name, MFSNAMELEN); 496 return (0); 497 } 498 499 /*ARGSUSED*/ 500 int 501 union_sync(mp, waitfor, cred, p) 502 struct mount *mp; 503 int waitfor; 504 struct ucred *cred; 505 struct proc *p; 506 { 507 508 /* 509 * XXX - Assumes no data cached at union layer. 510 */ 511 return (0); 512 } 513 514 /*ARGSUSED*/ 515 int 516 union_vget(mp, ino, vpp) 517 struct mount *mp; 518 ino_t ino; 519 struct vnode **vpp; 520 { 521 522 return (EOPNOTSUPP); 523 } 524 525 /*ARGSUSED*/ 526 int 527 union_fhtovp(mp, fidp, vpp) 528 struct mount *mp; 529 struct fid *fidp; 530 struct vnode **vpp; 531 { 532 533 return (EOPNOTSUPP); 534 } 535 536 /*ARGSUSED*/ 537 int 538 union_checkexp(mp, nam, exflagsp, credanonp) 539 struct mount *mp; 540 struct mbuf *nam; 541 int *exflagsp; 542 struct ucred **credanonp; 543 { 544 545 return (EOPNOTSUPP); 546 } 547 548 /*ARGSUSED*/ 549 int 550 union_vptofh(vp, fhp) 551 struct vnode *vp; 552 struct fid *fhp; 553 { 554 555 return (EOPNOTSUPP); 556 } 557 558 int 559 union_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p) 560 int *name; 561 u_int namelen; 562 void *oldp; 563 size_t *oldlenp; 564 void *newp; 565 size_t newlen; 566 struct proc *p; 567 { 568 return (EOPNOTSUPP); 569 } 570 571 extern const struct vnodeopv_desc union_vnodeop_opv_desc; 572 573 const struct vnodeopv_desc * const union_vnodeopv_descs[] = { 574 &union_vnodeop_opv_desc, 575 NULL, 576 }; 577 578 struct vfsops union_vfsops = { 579 MOUNT_UNION, 580 union_mount, 581 union_start, 582 union_unmount, 583 union_root, 584 union_quotactl, 585 union_statfs, 586 union_sync, 587 union_vget, 588 union_fhtovp, 589 union_vptofh, 590 union_init, 591 NULL, 592 union_done, 593 union_sysctl, 594 NULL, /* vfs_mountroot */ 595 union_checkexp, 596 union_vnodeopv_descs, 597 }; 598
Indexes created Mon Oct 13 08:09:50 GMT 2025